JP2023183764A - Flocculation evaluation method, flocculation evaluation device, flocculation treatment method, and flocculation treatment system - Google Patents

Abstract

To provide a flocculation evaluation method and a flocculation evaluation device that properly evaluate a flocculation state in flocculation treatment.SOLUTION: In a flocculation evaluation method, a flocculation state in flocculation treatment is evaluated, on the basis of water quality information on both water quality of clear water and water quality of concentrated water of a solid-liquid separation apparatus 10 which separates water to be evaluated containing flocculated flocks obtained in the flocculation treatment into clear water and concentrated water.SELECTED DRAWING: Figure 1

Description

The present invention relates to an agglutination evaluation method, an agglutination evaluation device, an agglutination treatment method, and an agglutination treatment system.

In water treatment, a flocculant such as an inorganic flocculant or a polymer flocculant is added to the water to be treated to flocculate suspended solids to form flocs, and the flocs are separated into solid-liquid using a solid-liquid separator. A flocculation process is performed.

In this type of coagulation treatment, a part of the water to be treated or a part of the water to be treated after addition of a coagulant is separated and passed through a solid-liquid separator separate from the main coagulation solid-liquid separator. It is known that the quality of flocculation can be evaluated based on the separability of flocs, which can be determined by measuring the quality of the treated water, and that the flocculation conditions of the main flocculation solid-liquid separation device can be controlled based on the evaluation results. (For example, see Patent Document 1).

When treating water with low turbidity, a one-stage solid-liquid separator may not be able to sufficiently separate particles, and the state of aggregation may not be appropriately evaluated even if the quality of the treated water is measured. In addition, when trying to measure the quality of the water treated in the solid-liquid separator and evaluate or control the flocculation state based on the separability of flocs, the separation is insufficient, so it is difficult to determine whether the flocculation state is good or not. In some cases, the quality of the treated water remains the same regardless of the condition, making it impossible to properly evaluate the flocculation state.

Japanese Patent Application Publication No. 2019-181342

An object of the present invention is to provide an agglomeration evaluation method, an agglutination evaluation device, and an agglutination treatment method and aggregation treatment system using the same, which can appropriately evaluate the agglomeration state in an aggregation treatment.

The present invention provides water quality information on both the quality of the clear water and the quality of the concentrated water of a solid-liquid separator that separates water to be evaluated containing flocculated flocs obtained in a coagulation treatment into clear water and concentrated water. This is an agglomeration evaluation method for evaluating the agglomeration state in the aggregation treatment based on the above-described aggregation treatment.

In the flocculation evaluation method, it is preferable that the water quality information is a turbidity difference between the turbidity of the concentrated water and the turbidity of the clear water.

In the aggregation evaluation method, it is preferable that when the turbidity difference becomes small, it is determined that the aggregation is deteriorated, and when the turbidity difference becomes large, it is determined that the aggregation is good.

The present invention provides a solid-liquid separation means for separating water to be evaluated containing flocculated flocs obtained by a flocculation treatment into clear water and concentrated water, a clear water quality measuring means for measuring the quality of the clear water, and a clear water quality measuring means for measuring the water quality of the clear water; A flocculation evaluation device, comprising a concentrated water quality measuring means for measuring the water quality of the concentrated water, and evaluating the flocculation state in the flocculation treatment based on water quality information of both the water quality of the clear water and the water quality of the concentrated water. be.

In the flocculation evaluation device, it is preferable that the water quality information is a turbidity difference between the turbidity of the concentrated water and the turbidity of the clear water.

In the aggregation evaluation device, it is preferable that when the turbidity difference becomes small, it is determined that the aggregation has worsened, and when the turbidity difference becomes large, it is determined that the aggregation is good.

The present invention includes a flocculation treatment step in which a flocculant is added to the water to be treated to perform flocculation treatment, and the water to be evaluated containing flocculated flocs obtained in the flocculation treatment step is separated into clear water and concentrated water. The present invention is a flocculation treatment method in which the flocculation state in the flocculation treatment is evaluated based on water quality information of both the water quality of the clear water and the water quality of the concentrated water of the solid-liquid separator.

In the flocculation treatment method, it is preferable to control the conditions of flocculation treatment in the flocculation treatment step based on water quality information of both the water quality of the clear water and the water quality of the concentrated water.

In the flocculation treatment method, it is preferable that the water quality information is a turbidity difference between the turbidity of the concentrated water and the turbidity of the clear water.

In the aggregation treatment method, it is preferable that when the turbidity difference becomes small, it is determined that the aggregation has worsened, and when the turbidity difference becomes large, it is determined that the aggregation is good.

The present invention provides a flocculation treatment device that performs flocculation treatment by adding a flocculant to water to be treated, and a flocculation treatment device that separates water to be evaluated containing flocculated flocs obtained by the flocculation treatment device into clear water and concentrated water. A liquid separating means, a clear water quality measuring means for measuring the water quality of the clear water, and a concentrated water water quality measuring means for measuring the water quality of the concentrated water, This is a flocculation treatment system that evaluates the flocculation state in the flocculation treatment based on both types of water quality information.

Preferably, the flocculation treatment system further includes a control means for controlling conditions for flocculation treatment in the flocculation treatment device based on water quality information on both the quality of the clear water and the water quality of the concentrated water.

In the flocculation treatment system, it is preferable that the water quality information is a turbidity difference between the turbidity of the concentrated water and the turbidity of the clear water.

In the aggregation treatment system, it is preferable that when the turbidity difference becomes small, it is determined that the aggregation is deteriorated, and when the turbidity difference becomes large, it is determined that the aggregation is good.

According to the present invention, it is possible to provide an agglomeration evaluation method and an agglomeration evaluation apparatus that can appropriately evaluate the agglomeration state in an agglomeration treatment, as well as an aggregation treatment method and an aggregation treatment system using the same.

1 is a schematic configuration diagram showing an example of an agglomeration evaluation device according to an embodiment of the present invention. It is a schematic diagram showing an example of the flow path cross section of the curved channel which is an example of the solid-liquid separation device in the agglomeration evaluation device according to the embodiment of the present invention. FIG. 3 is a schematic configuration diagram showing another example of the agglomeration evaluation device according to the embodiment of the present invention. 1 is a schematic configuration diagram showing an example of an agglomeration processing system including an aggregation evaluation device according to an embodiment of the present invention. 3 is a graph showing changes in turbidity over time in Example 1. 3 is a graph showing changes in turbidity over time in Comparative Example 1.

Embodiments of the present invention will be described below. This embodiment is an example of implementing the present invention, and the present invention is not limited to this embodiment.

An example of an agglomeration evaluation device according to an embodiment of the present invention is schematically shown in FIG. 1, and its configuration will be described.

The flocculation evaluation apparatus 1 in FIG. 1 includes a solid-liquid separator 10 as a solid-liquid separation means for separating evaluated water containing flocculated flocs obtained by flocculation treatment into clear water and concentrated water. A clear water quality measuring device 12 is provided as a clear water quality measuring means for measuring the water quality of concentrated water, and a concentrated water quality measuring device 14 is provided as a concentrated water quality measuring means for measuring the water quality of concentrated water.

In the flocculation evaluation apparatus 1 shown in FIG. 1, an evaluation target water pipe 16 is connected to the inlet of the solid-liquid separator 10. A clear water pipe 18 is connected to a clear water outlet of the solid-liquid separator 10, and a concentrated water pipe 20 is connected to a concentrated water outlet. A clear water quality measuring device 12 is installed in the clear water pipe 18, and a concentrated water quality measuring device 14 is installed in the concentrated water pipe 20.

The agglomeration evaluation method and the operation of the agglomeration evaluation device 1 according to the present embodiment will be described.

The evaluated water containing flocculated flocs obtained in the coagulation process is supplied to the solid-liquid separator 10 through the evaluated water piping 16, and is separated into clear water and concentrated water in the solid-liquid separator 10. separation process). Clear water is discharged through clear water piping 18 and concentrated water is discharged through concentrated water piping 20.

In the clear water pipe 18, the quality of the clear water is measured by the clear water quality measurement device 12, and the water quality information of the clear water is acquired (clear water quality measurement step). In the concentrated water piping 20, the quality of the concentrated water is measured by the concentrated water quality measuring device 14, and water quality information of the concentrated water is acquired (concentrated water quality measuring step).

In the flocculation evaluation method and flocculation evaluation apparatus according to the present embodiment, the solid-liquid separator 10 performs separation into a clarification side and a concentration side, and evaluates the flocculation state based on water quality information on both the clarification side and the concentration side. Thereby, the aggregation state in the aggregation process can be appropriately evaluated. Moreover, even if the water to be evaluated has a low turbidity (for example, 5 degrees or less), the flocculation state in the flocculation treatment can be appropriately evaluated. Even if the separation in the solid-liquid separator 10 is insufficient, the state of aggregation in the aggregation process can be appropriately evaluated.

The solid-liquid separator 10 includes, for example, a cell that separates using a Dean vortex developed by a curved channel using bent pipes, and a solid-liquid separator that uses gravity sedimentation, membrane filtration, sand filtration, etc. From the viewpoint of speed and maintainability, a curved channel using a Dean vortex is preferable.

The curved channel is a spiral channel in which piping is formed in a spiral shape and has a to-be-treated liquid inlet for inflowing the to-be-treated liquid (water to be evaluated) and one rectangular flow path for the fluid to flow. , a clear water outlet separated from, for example, the outer circumferential side of the flow path for discharging clear water (channel treated water), and a clear water outlet separated from, for example, the inner circumference side of the flow path for discharging concentrated water (channel concentrated water). and a concentrated water outlet. Figure 2 shows a cross section of the curved channel. When a liquid to be treated containing solid particles (agglomerates) is introduced into the spiral channel from the inlet of the liquid to be treated, the cross section of the rectangular channel has two parts. A secondary flow (Dean vortex) is generated. This is due to the outward flow due to centrifugal force and the inward pressure caused by the flow that is trying to proceed straight to be forcibly bent by the outer wall.

Solid particles are said to gather on the inner circumferential side of this secondary flow (Dean vortex), but depending on the balance of the density of the solid particles, the flux of the fluid flowing in the flow path, the curvature of the flow path, etc. Particles may also collect on the outer periphery. In this case, the curved channel may have a clear water outlet separated from the inner circumference side of the flow path and a concentrated water outlet separated from the outer circumference side of the flow path. By adjusting the balance of the density of solid particles in the curved channel, the flux of the fluid flowing in the flow path, the curvature of the flow path, etc., the curved channel can reduce the density difference between solid particles and liquid, gravity, and fluid dynamics. Solid particles can be separated from the liquid to be treated by the chemical action.

The curved channel is not particularly limited as long as it has a flow path including a wall surface with curvature. A curved channel is, for example, a pipe formed in a spiral shape and having one flow path including a wall surface having a curvature. The cross-sectional shape of the flow path of the curved channel may be rectangular, circular, elliptical, etc., and in order to form a Dean vortex, it is desirable that the cross-sectional shape of the flow path is rectangular. That is, the curved channel has a flow path including an upper wall surface, a lower wall surface, and a side wall surface having curvature.

Depending on the flow rate of the liquid to be treated, whether the solid particles are concentrated inside or outside the curved channel changes, so the channel treated water piping and channel concentrated water piping are It may be changed as appropriate.

Preferably, the curved channel has a predetermined curvature, length, and width determined depending on the purpose of separating solid particles.

The specifications of the curved channel that are optimal for separating solid particles vary depending on the properties of the solid particles (density, particle size, etc.), so it is desirable to determine them using flow analysis software. Examples of the flow analysis software include "ANSYS Fluent" (ANSYS, Inc.).

The water quality of clear water and concentrated water may be measured by switching valves or the like, using one water quality measuring device.

The water quality to be measured includes, for example, turbidity, chromaticity, organic matter concentration (TOC), pH, images, and numerical values obtained by image analysis (e.g., particle number, particle size, floc color, and measurements using machine learning and deep learning). image analysis and floc condition evaluation). When evaluating the flocculation state, a turbidity meter that measures turbidity is preferable, taking into consideration the price of the water quality measuring device.

The water quality information is, for example, the turbidity difference between the turbidity of concentrated water and the turbidity of clear water, the ratio between the turbidity of concentrated water and the turbidity of clear water, or the turbidity of concentrated water and the turbidity of clear water. Examples include the ratio of clear water turbidity to the total value of . For example, when using the turbidity difference between the turbidity of concentrated water and the turbidity of clear water as water quality information, when the flocculation is good, the turbidity of the concentrated water increases in the solid-liquid separator 10, and the turbidity of the concentrated water increases. The difference in turbidity increases. On the other hand, if the aggregation state is poor, the difference in turbidity between concentrated water and clear water becomes small. Therefore, when the turbidity difference between the turbidity of the concentrated water and the turbidity of the clear water becomes small, it is determined that the aggregation is deteriorated, and when the turbidity difference becomes large, it is determined that the aggregation is good.

As an evaluation water quality measuring means for measuring the water quality of the evaluation water, an evaluation water quality measuring device is installed, for example, in the evaluation water piping 16, and the water quality of the evaluation water is measured. The flocculation state in the flocculation process may be evaluated based on the water quality information of the clear water quality and the concentrated water quality of the liquid separation device 10. Thereby, the agglomeration state in the aggregation process can be evaluated more appropriately.

The flocculation evaluation device includes an output section as an output means for outputting a predetermined output based on the quality of clear water measured by the clear water quality measuring device 12 and the quality of concentrated water measured by the concentrated water quality measuring device 14. You can. The clear water quality measuring device 12 and the concentrated water quality measuring device 14 may be provided with an output section. The output unit may be installed in each of the clear water quality measuring device 12 and the concentrated water quality measuring device 14, or one output unit may be installed in common. Based on the water quality of the clear water measured by the clear water quality measuring device 12 and the water quality of the concentrated water measured by the concentrated water water quality measuring device 14, a predetermined output such as an alarm to notify deterioration of aggregation is performed at the output section. (output process).

As the output from the output unit, in addition to an audiovisually perceptible alarm such as a display or sound that indicates deterioration of aggregation, a response method for responding to a change in the aggregation state, etc. may be displayed. The output unit is not particularly limited as long as it can display and output information, but examples include display means such as a liquid crystal display and organic EL display, and audio output means such as a speaker. It will be done. For example, methods of issuing an alarm include displaying it on a touch panel of a control panel, notifying an operator via Internet communication, and notifying a monitoring room or the like.

The output unit may issue an alarm, for example, when the turbidity difference between the turbidity of the concentrated water and the turbidity of the clear water falls below a predetermined threshold. The alarm threshold value may be set in advance to one value, or may be changed stepwise or proportionally depending on the water quality such as turbidity of the water to be treated.

In order to make the difference in turbidity between concentrated water and clear water more clear, solid-liquid separation may be performed in two or more stages. FIG. 3 shows an example of an agglomeration evaluation device in which solid-liquid separation is performed in two stages.

The flocculation evaluation apparatus 3 in FIG. 3 includes a first solid-liquid separator 30 and a second solid-liquid separator as a solid-liquid separation means for separating water to be evaluated containing flocculated flocs obtained by flocculation treatment into clear water and concentrated water. A liquid separation device 32, a clear water quality measuring device 36 as a clear water quality measuring means for measuring the water quality of clear water, a concentrated water quality measuring device 34 as a concentrated water quality measuring means for measuring the water quality of concentrated water, Equipped with.

In the flocculation evaluation device 3 of FIG. 3, an evaluation target water pipe 38 is connected to the inlet of the first solid-liquid separation device 30. The first clear water outlet of the first solid-liquid separator 30 and the inlet of the second solid-liquid separator 32 are connected by a first clear water pipe 40, and are connected to the first concentrated water outlet of the first solid-liquid separator 30. is connected to the first concentrated water pipe 42. A second clear water pipe 44 is connected to the second clear water outlet of the second solid-liquid separator 32, and a second concentrated water pipe 46 is connected to the second concentrated water outlet. A clear water quality measuring device 36 is installed in the second clear water pipe 44, and a concentrated water quality measuring device 34 is installed in the first concentrated water pipe 42.

The water to be evaluated containing flocculated flocs obtained by the coagulation process is supplied to the first solid-liquid separator 30 through the water to be evaluated piping 38, and in the first solid-liquid separator 30, the first clear water and the first concentrated water are separated. (first solid-liquid separation step). The first concentrated water is discharged through the first concentrated water pipe 42.

The first clear water obtained in the first solid-liquid separator 30 is supplied to the second solid-liquid separator 32 through the first clear water pipe 40, and in the second solid-liquid separator 32, the first clear water is mixed with the second clear water. 2 concentrated water (second solid-liquid separation step). The second clear water is discharged through the second clear water pipe 44 , and the second concentrated water is discharged through the second concentrated water pipe 46 .

In the second clear water pipe 44, the quality of the second clear water is measured by the clear water quality measurement device 36, and water quality information of the second clear water is acquired (clear water quality measurement step). In the first concentrated water piping 42, the quality of the first concentrated water is measured by the concentrated water quality measuring device 34, and water quality information of the first concentrated water is acquired (concentrated water quality measuring step).

In the flocculation evaluation method and flocculation evaluation apparatus according to the present embodiment, the first solid-liquid separator 30 performs separation into the clarifying side and the concentration side, and the clarifying side of the first solid-liquid separator 30 is separated into the second solid-liquid separator 30. At step 32, the water is separated into the clarification side and the concentration side, and the flocculation state is evaluated based on the water quality information from both the final stage clarification side and the first stage concentration side. Thereby, the aggregation state in the aggregation process can be appropriately evaluated.

By performing solid-liquid separation in two or more stages, the difference in turbidity between the clarification side and the concentration side becomes clear, making it easier to use for control.

When solid-liquid separation is performed in two or more stages, the water quality measurement of the clear water can be performed on the clear water in the final stage solid-liquid separator, and the water quality measurement on the concentrated water can be performed on the water quality of the concentrated water in the first stage solid-liquid separator. Just follow the water. Alternatively, the water quality may be measured for the concentrated water in each stage and the clarified water in the final stage, and the flocculation state may be evaluated based on the water quality information on the concentrated water in each stage and the clarified water in the final stage.

Depending on the quality of the concentrated water and the clear water, the conditions of the flocculation process in the flocculation treatment device that is the main flow may be controlled. An example of an aggregation treatment system in such a case is shown in FIG.

The flocculation treatment system 7 in FIG. 4 includes a flocculation treatment device 5 as a flocculation treatment means for performing flocculation treatment by adding a flocculant to the water to be treated, and a flocculation evaluation device 3 for evaluating the flocculation state in the flocculation treatment. . The flocculation evaluation device 3 in the flocculation treatment system 7 includes a control device 70 as a control means for controlling the conditions of flocculation treatment in the flocculation treatment device 5 based on water quality information of both the water quality of clear water and the water quality of concentrated water. Good too.

The flocculation evaluation device 3 serves as a solid-liquid separation means for separating the evaluated water containing flocculated flocs obtained by the flocculation treatment in the flocculation treatment device 5 into clear water and concentrated water. 2 solid-liquid separator 32, a clear water quality measuring device 36 as a clear water quality measuring means for measuring the water quality of clear water, and a concentrated water quality measuring device 34 as a concentrated water quality measuring means for measuring the water quality of concentrated water. and.

The coagulation treatment device 5 includes a coagulation mixing tank 50 as a coagulation mixing means for adding and mixing a coagulant to the water to be treated, and a separation device for separating the coagulation concentrated water containing formed flocs and treated water. As a means, a separation device 52 is provided. The flocculation treatment device 5 may provide a floc formation tank between the flocculation mixing tank 50 and the separation device 52 as a floc formation means for forming flocs in the mixed liquid mixture. The aggregation treatment device 5 may include a sand filter device downstream of the separation device 52 as a filtration treatment means that performs a filtration treatment on the treated water.

In the coagulation treatment device 5 , a water pipe 54 to be treated is connected to the inlet of the coagulation mixing tank 50 . The outlet of the coagulation mixing tank 50 and the inlet of the separation device 52 are connected by a coagulation liquid piping 56. A treated water pipe 58 is connected to the outlet of the separation device 52. A flocculant addition pipe 60 is connected to the chemical inlet of the flocculation mixing tank 50 as a flocculant addition means.

The evaluated water outlet of the flocculation mixing tank 50 and the inlet of the first solid-liquid separator 30 are connected by an evaluated water pipe 38. The first clear water outlet of the first solid-liquid separator 30 and the inlet of the second solid-liquid separator 32 are connected by a first clear water pipe 40, and are connected to the first concentrated water outlet of the first solid-liquid separator 30. is connected to the first concentrated water pipe 42. A second clear water pipe 44 is connected to the second clear water outlet of the second solid-liquid separator 32, and a second concentrated water pipe 46 is connected to the second concentrated water outlet. A clear water quality measuring device 36 is installed in the second clear water pipe 44, and a concentrated water quality measuring device 34 is installed in the first concentrated water pipe 42.

The control device 70 includes a flocculant addition amount adjusting means (not shown) installed in the concentrated water quality measurement device 34, the clear water quality measurement device 36, and the flocculant addition piping 60 for adjusting the amount of flocculant added, for example, The valves, pumps, etc. are connected to each other by wired or wireless electrical connections.

For example, the water to be treated containing suspended matter and the like is sent to the coagulation mixing tank 50 through the water to be treated piping 54 . In the flocculant-mixing tank 50, a flocculant is added to the water to be treated through the flocculant addition pipe 60, and the water is rapidly stirred to perform flocculation (coagulation-mixing step) to form flocs (floc-forming step). A flocculation tank may be provided after the flocculation mixing tank 50, and flocs may be formed in the flocculation tank. In the coagulation mixing tank 50, a pH adjuster may be added to the water to be treated to adjust the pH (pH adjustment step). The flocculated liquid containing the formed flocs is sent to the separation device 52 through the flocculation liquid piping 56, where solid-liquid separation is performed by gravity sedimentation, filtration, etc., and treated water is obtained. (Separation process) (The above is the aggregation treatment process). The treated water may be sent to a sand filtration device downstream of the separation device 52 and subjected to filtration treatment in the sand filtration device (filtration treatment step).

The flocculated mixed water containing flocculated flocs obtained in the flocculation treatment device 5 is branched from the flocculation mixing tank 50 and is supplied as water to be evaluated to the first solid-liquid separator 30 through the water to be evaluated piping 38. In the separation device 30, the water is separated into first clear water and first concentrated water (first solid-liquid separation step). The first concentrated water is discharged through the first concentrated water pipe 42.

The first clear water obtained in the first solid-liquid separator 30 is supplied to the second solid-liquid separator 32 through the first clear water pipe 40, and in the second solid-liquid separator 32, the first clear water is mixed with the second clear water. 2 concentrated water (second solid-liquid separation step). The second clear water is discharged through the second clear water pipe 44 , and the second concentrated water is discharged through the second concentrated water pipe 46 .

In the second clear water pipe 44, the quality of the second clear water is measured by the clear water quality measurement device 36, and water quality information of the second clear water is acquired (clear water quality measurement step). In the first concentrated water piping 42, the quality of the first concentrated water is measured by the concentrated water quality measuring device 34, and water quality information of the first concentrated water is acquired (concentrated water quality measuring step).

In the flocculation evaluation method and flocculation evaluation apparatus according to the present embodiment, the first solid-liquid separator 30 and the second solid-liquid separator 32 perform separation into a clarifying side and a concentrating side, and the final stage clarifying side and the first stage Evaluate the flocculation state based on water quality information on both the concentration side. Thereby, the aggregation state in the aggregation process can be appropriately evaluated.

Based on this water quality measurement result, the control device 70 controls the coagulation conditions such as the injection rate of the coagulant in the coagulation treatment device 5 (control step).

The control device 70 is composed of, for example, a microcomputer including a computing means such as a CPU that computes a program, a storage means such as a ROM and a RAM that stores the program and the results of the computation, and an electronic circuit. For example, the control device 70 controls the flocculation process in the flocculation treatment device 5 based on the water quality information of both the clear water quality and the concentrated water quality measured by the clear water quality measuring device 36 and the concentrated water quality measuring device 34. It has the ability to control conditions. For example, the control device 70 controls the addition of flocculant in the flocculant treatment device 5 based on the water quality information of both the clear water quality and the concentrated water quality measured by the clear water quality measuring device 36 and the concentrated water quality measuring device 34. It has a function of controlling the amount of flocculant added to the water to be treated by adjusting the flow rate of the pump installed in the piping 60, the opening/closing degree of the valve, etc.

As the flocculant used in the flocculation treatment system according to this embodiment, at least one of an inorganic flocculant and a polymer flocculant is used.

Examples of the inorganic flocculant include iron-based inorganic flocculants such as ferric chloride and polyferric sulfate, and aluminum-based inorganic flocculants such as aluminum sulfate and polyaluminum chloride (PAC).

The amount of the inorganic flocculant added is, for example, in the range of 1 to 100 mg/L.

Examples of polymer flocculants include nonionic polymer flocculants, anionic polymer flocculants, cationic polymer flocculants, etc., but examples include polyacrylamide, sodium polyacrylate, acrylamide, etc. Examples include acrylate copolymers, sodium acrylamide propane sulfonate, chitosan, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, and polyamidine. The polymer flocculants may be used alone or in combination of two or more.

The amount of the polymer flocculant added is, for example, in the range of 0.1 to 2 mg/L.

Examples of pH adjusters include acids such as hydrochloric acid and sulfuric acid, and alkaline agents such as sodium hydroxide. The pH may be adjusted to a range of 4 to 11, for example.

The liquid temperature in the flocculation treatment (coagulation mixing step, floc formation step, separation step) is not particularly limited, and is, for example, in the range of 15 to 35°C. Since separation properties vary depending on viscosity and other factors, it is desirable to adjust the liquid temperature to be as constant as possible.

The water to be treated, which is the target of treatment in the coagulation treatment system, is, for example, water containing suspended substances, and includes, for example, river water, industrial water, wastewater, and the like.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<Example 1>
Solid-liquid separation of the test water was performed using the flocculation evaluation apparatus shown in FIG. 3 under the following conditions. Pure water was added 80 minutes to 260 minutes after the start of treatment to intentionally worsen aggregation. Figure 5 shows the change in turbidity over time.

(Experimental conditions)
Test water: turbidity 2 degrees, flocculant: polyaluminum chloride (PAC) 40 ppm, pH: 4.0
First solid-liquid separator, second solid-liquid separator: Bent channel Clear water quality measuring device, concentrated water quality measuring device: Turbidity meter (manufactured by OPTEX, TC-100)

<Comparative example 1>
Solid-liquid separation of the same test water as in Example 1 was performed using the flocculation evaluation apparatus shown in FIG. In Comparative Example 1, the turbidity on the clarification side was measured, and the treatment was performed without measuring the turbidity on the concentration side. Figure 6 shows the change in turbidity over time.

In Example 1, it can be confirmed that when the aggregation is good, the difference in turbidity between the concentrated side and the clarified side is large, and when the aggregation is deteriorated, the difference becomes small.

In Example 1, the pH of the test water was adjusted to 7.0±0.1 by adding an aqueous sodium hydroxide solution at 260 minutes, assuming that deterioration of aggregation was detected. After the difference in turbidity fell below a predetermined value and a predetermined time had elapsed, the flocculation conditions were reviewed (in this experiment, an aqueous sodium hydroxide solution was added to optimize the pH). The difference has increased again.

Looking at the results of the turbidity on the clarified side of Comparative Example 1, it can be seen that there is no change in the turbidity regardless of the quality of aggregation. If there is no change, it cannot be used to control the aggregation treatment device.

Table 1 shows the turbidity of the treated water due to coagulation and precipitation at each time.

In Example 1, it was possible to detect the deterioration of aggregation and recover the agglomeration state, and the increase in turbidity of the sedimentation treated water was temporary, and then it recovered. In Comparative Example 1, the turbidity of the precipitated water continued to rise because deterioration of aggregation could not be detected.

In this manner, the agglomeration state in the aggregation treatment could be appropriately evaluated by the method of the example.

1, 3 Coagulation evaluation device, 5 Coagulation treatment device, 7 Coagulation treatment system, 10 Solid-liquid separation device, 12, 36 Clear water quality measurement device, 14, 34 Concentrated water quality measurement device, 16, 38 Water piping to be evaluated, 18 Clear water piping, 20 Concentrated water piping, 30 First solid-liquid separator, 32 Second solid-liquid separator, 40 First clear water piping, 42 First concentrated water piping, 44 Second clear water piping, 46 Second concentration Water piping, 50 coagulation mixing tank, 52 separation device, 54 treated water piping, 56 flocculating liquid piping, 58 treated water piping, 60 flocculant addition piping, 70 control device.

Claims (10)

The flocculation process is performed based on the water quality information of both the clear water quality and the concentrated water quality of the solid-liquid separator that separates the evaluated water containing flocculated flocs obtained by the flocculation treatment into clear water and concentrated water. A flocculation evaluation method characterized by evaluating the flocculation state during processing. The agglomeration evaluation method according to claim 1,
A flocculation evaluation method characterized in that the water quality information is a turbidity difference between the turbidity of the concentrated water and the turbidity of the clear water. The agglomeration evaluation method according to claim 2,
A flocculation evaluation method characterized in that when the turbidity difference becomes small, it is determined that aggregation is deteriorated, and when the turbidity difference becomes large, it is determined that aggregation is good. solid-liquid separation means for separating evaluated water containing flocculated flocs obtained in the flocculation treatment into clear water and concentrated water;
Clear water quality measuring means for measuring the quality of the clear water;
Concentrated water quality measuring means for measuring the water quality of the concentrated water;
Equipped with
A flocculation evaluation device characterized in that the flocculation state in the flocculation process is evaluated based on water quality information of both the water quality of the clear water and the water quality of the concentrated water. The agglomeration evaluation device according to claim 4,
A flocculation evaluation device, wherein the water quality information is a turbidity difference between the turbidity of the concentrated water and the turbidity of the clear water. The agglomeration evaluation device according to claim 5,
An agglomeration evaluation device characterized in that when the turbidity difference becomes small, it is determined that the aggregation is deteriorated, and when the turbidity difference becomes large, it is determined that the aggregation is good. Including a flocculation treatment process in which a flocculant is added to the water to be treated to perform flocculation treatment,
Based on the water quality information of both the water quality of the clear water and the water quality of the concentrated water of a solid-liquid separator that separates the evaluated water containing the flocculated flocs obtained in the coagulation treatment step into clear water and concentrated water. An aggregation treatment method characterized by evaluating the aggregation state in the aggregation treatment. The aggregation treatment method according to claim 7,
A flocculation treatment method, characterized in that conditions for flocculation treatment in the flocculation treatment step are controlled based on water quality information of both the water quality of the clear water and the water quality of the concentrated water. A flocculation treatment device that performs flocculation treatment by adding a flocculant to water to be treated;
solid-liquid separation means for separating the water to be evaluated containing the flocculated flocs obtained by the flocculation treatment device into clear water and concentrated water;
Clear water quality measuring means for measuring the quality of the clear water;
Concentrated water quality measuring means for measuring the water quality of the concentrated water;
Equipped with
A flocculation treatment system, characterized in that the flocculation state in the flocculation treatment is evaluated based on water quality information of both the water quality of the clear water and the water quality of the concentrated water. The aggregation treatment system according to claim 9,
A flocculation treatment system further comprising a control means for controlling conditions for flocculation treatment in the flocculation treatment apparatus based on water quality information of both the water quality of the clear water and the water quality of the concentrated water.